Owner-Draw List Boxes Limited to 8160 Items

ID Number: Q71414

3.00

WINDOWS

Summary:

Owner-draw list boxes in Microsoft Windows version 3.00 can hold up to

8160 items. The list box returns an error if an application attempts

to add additional items.

In Windows 3.00, a list box is limited to 64K of data for its items.

Each item in an owner-draw list box takes up 8 bytes of this data,

four of which hold the application-supplied 32-bit value passed with

the LB_ADDSTRING message.

The list box uses 256 bytes of the 64K segment for internal storage,

and uses the rest for items. This yields room for 8160 items:

(64K segment - 256 bytes) / (8 bytes per item)